The difference between css class class

CSS is a technology used for web page layout. It controls the appearance and layout of various elements on a web page by defining styles to achieve beautiful and readable pages. In CSS, there are two concepts: class and tag. Although they are both used for styling, they have different purposes and ways of using them. This article will explore the difference and usage of classes and tags.

1. Tags

Tags are the beginning and end of defined elements in HTML. They define different parts of the web page. For example, the

tag defines the title of the page, the

tag defines a paragraph, and the

tag is used to group HTML documents so that CSS can control styles for these groups. The main function of tags is to provide pure HTML structure for web page elements, and their styles and effects are controlled by CSS.

CSS allows you to select specific HTML tags for styling. Tags can be selected via:

h1 {
    color: red;
}

In this example, we set the color of all <h1></h1> elements. However, this approach becomes less applicable if we need to set different <h1></h1> elements. At this time, we need to use classes.

2. Class

A class is an attribute in HTML5 that can be used to define a specific style for one or more elements that appear in an HTML page. Class names are used to represent styles and apply them to one or more HTML elements. It can be named by any name, but it is best to use a short name that reflects the purpose of the element to facilitate code writing and maintenance.

In CSV, the class style starts with ".", followed by the class name, such as: .classname{...}. Here is an example:

.red {
    color: red;
}

In this example, we define a class named "red", which is applied to HTML elements. Only elements to which this class is applied will have a red color. Here's how to apply a class name:

<p class="red">这个段落是红色。</p> 

In this example, we apply the "red" class to the <p></p> element and give it a red font color. Elements to which the class name is applied will use the class's style.

3. The difference between classes and tags

Generally speaking, using tags to control styles is more global. The advantage of this is that the tag style can be used throughout the website, so that the style is unified and maintenance and development are more convenient. However, in some cases, the label style cannot be precisely controlled, and in this case, you need to use classes to control the style. The role of classes is local control. The use of classes is more targeted and different styles can be set according to specific situations.

In general, classes and tags each have their own advantages and disadvantages, and the reasonable use of CSS layout needs to be considered and selected under specific circumstances.

4. Summary

The above discussed the difference and usage of classes and labels. Label styles are suitable for global control, while class styles are suitable for local control. In specific cases, we need to use different methods for style control to achieve a unified, easy-to-maintain and beautiful web page effect.

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